In certain types of security seals, a stranded cable is used as a shackle. A housing is provided with apertures for receiving the ends of a length of cable. One end may be permanently attached in one aperture and the other housing aperture has means allowing the cable to enter freely but locks the cable against reverse movement. One problem with such devices has been that of providing a secure and rugged housing at minimum cost. Another problem has been that of providing a housing structure that provides a minimum distance between the shackle apertures for maximum security against tampering, yet allows room for adequate internal cable locking mechanisms.